Apparatus for doping airplane wings



1,503,478 F. O. CLEMENTS APPARATUS FOR'DOPING AIRPLANE WINGS Aug. 5, H924;

Filed Auz. 28. 1918 4 Sheets-Sheet 1- F. o. CLE'MENTS Aug. 5 ,7 192%. 1,503,478

APPARATUS FOR DOPING AIRPLANE wmes Filed Aux. 28 1918 4 Sheets-Sheet 2 F. O. CLEMENTS APPARATUS FOR DOPING AIRPLANE WINGS ZIUQJ EP 4 'S eets-Sheet 3 Filed ill Aug. 5, m4 1,503,478

F. o. CLEMENTS- APPARATUS FOR DOPING AIRPLANE WI NGS Filed Aug. 28. 1918 4 Sheets-Shet 4 Patented Aug. 5, 1924.

STATES FRANK 0. CLEMENTS, or DAYTON, onro,

ASSIGNOR, BY MESNE ASSIGNMENTS, TO

DAYTON-WRIGHT COMPANY, OF DAYTON, OHIO, A CORPORATION OF DELAWARE.

, APPARATUS FOR DOPING AIRPLANE WINGS.

Application filed August 28,.1918. Serial No. 251,760.

To all whom it may concern:

Be it known that'I, FRANK O. CLEMENTs, a citizen of the United States of America. residing at Dayton, county of Montgomery, State of Ohio, have invented certain new and useful Improvements in Apparatus for Doping Airplane Wings, of which the following is a full, clear, and exact description.

This invention relates to the doping of wings and other parts of airplanes and more .particularly to amethod of doping those parts without the development of the objectionable blooming, and to an apparatus for carrying that method into effect.

In the manufacture 'of airplanes, as at present carriedpon, the wings, the ailerons, the tail and rudder members and parts of the fuselage, are covered with fabric. That fabric is coated or impregnated with dope. This dope normally consists of cellulose compounds, such as nitrates or acetates, dis solved in some solvent, such as amyl acetate, acetone etc. In doping the wings or other fabric covered parts of the airplane the dope solution is applied to the fabric which is then allowed to dry, the solvent evaporating and leaving a film of cellulose material on and within the fabric. If this drying or evaporation takes placein an atmosphere of relatively high humidity some of the component parts of the'dope will absorb moisture from the atmosphere and instead of drying in a continuous water-proof membrane or film it will dry as a white, somewhat granular, depositxwhich looks quite similar to white-wash and is not a weather resisting film nor a water-proof plastic. This phenomenon ofdoping is called blooming and is quite objectionable.

The principal object of the present invention is to provide a method of dopingairplane fabrics adapted to prevent this blooming, and to provide a practicable'form of apparatus for carrying that method into effective operation.

Other objects and advantages of the present invention will be apparent from the description of the invention set outbelow, in which description reference is made to the accompanying drawing which illustrates several forms of apparatus adapted for car- .ryingout my method of doping.

In the drawings, in which like characters of reference designate like/parts throughout the several views thereof.

Fig. l is a view partly in elevation and partly in section showing a drying booth used in carrying my method into effect which booth is adapted for receiving a single wing;

Fig. 2 is a transverse sectional view of the apparatus of Fig. 1. along the line 22 thereof;

Fig. 3 is a horizontal sectional view through a modified form of apparatus adapteddfor receiving three wings at one time; an

Fig. 4 is a transverse sectional view through the form of apparatus illustrated in Fig. 3, along the line 4c4 thereof.

As stated briefly above, in the present method of airplane manufacture the wings, the ailerons, the tail and rudder members and parts of the fuselage are covered with fabric. In order to give a substantial period of life to this fabric, and to make it stronger and more durable in service, it is necessary to so treat. it as to cause shrinkage of the fabric and to make it weather-proof. For treating this fabric a so called dope is used, which consists of some cellulose compound, generally cellulose nitrate or cellu lose acetate, dissolved in some readily vaporizable solvent, suchas amyl acetate or acetone. The dope is generally applied to the fabric by means-of brushes, and the present approved practice requires the application of four coats to secure a film or membrane of the desired characteristics. The practice heretofore has been toplace the fabric covered pieces of the apparatus however, the relative humidity of the at-- mosphere is high it has been found that during the drying process some moisture from the atmosphere will be absorbed by in a suitable supporting rack,to apply the v the dope. This gives rise'to blooming. It

has been found that these white spots, or

bloorns represent cellulose precipitated from solution'by water andthat such material is granular in form and does not cause proper shrinkage of the fabric or rotect a am.- the Weather.

I have discovered that by properly oonditioningthe air'in which the doped fabric is dried, blooming canbe easily prevented.

In other-words it is merelynecessary toso treat the air that the relative humid1tythereof may be lowered substantially below satur .tion. This can be done, of course, in

several ways, as-for instance by lowering" the temperature of the air, before it is use for drying purposes, sufiiciently to condense therefrom a substantial portion of the contained moisture. Another and. sim ler method of accomplishing the same resu t is to heat the atmospheric air surrounding the wing that is being, dried suificiently'to lower the,r'elatively humidity thereof. In other words by raising the temperature'of the air,

its moisture content remaining constant, the relative humidity of such air will decrease with the increased temperature. Experilowered 'sufiiciently to prevent bloomin In actual practice, however, I have use as the simplest and preferred adaptation of my invention, that method of conditioning air whichconsists of heating the air in order to lower its relative humidity. And for carrying that method into effect I have made use of drying booths containing heating elements adapted to raise the temperature within such boothsabove the temperature of saturation of the atmospheric'air'therein.

In carrying out this method-I have not found it necessary to use completely closed booths. Instead I have used booths similar to those disclosed in the drawing. Inasmuch as the wings of airplanes because i of their unwieldy proportions, of their large expanse of fabric covering and Iof the necessity for insuring; a perfect doping of such fabric, constitute the most difiicult phase of the doping operations, and since the proper doping of the wings. eradicates the major ortion of-the doping difficulties, I have llustrated my doping apparatus as adapted. for use in the doping of wings. It is of course obvious that the method forming the substance of my invention is applicable not only to the doping .of the wing covering but to the doping of fabric used in any-other part of the airplane.

And it is equally obvious that with simple this frame.

mechanical chan ges the apparatus disclosed could be adapted for use in connection with an other parts of the air lane.

n Fi s. 1 and 2, which illustrate a simple.

form 0 apparatus for carrying out my method of doping, 10 is a (track carrying member supported from the ceiling by a pluralityof beams 11, Any other desired form of supporting mechanism may be used.- The member 10, in the form of apparatus heretofore used, is of wood, is substantially Y 12 inches wide and a little more than twice i the length of rthe wing to be doped. This member 10 in addition to being a track carrying member constitutes the upper side of a framework, the other' or lower side of the framework consisting of two heavy timbers 12, firmly attached to the' floor and braced by means of beams 13. At each end of the member 10 and the beams 12 arelocated a plurality of uprights '14, .there beingtwo of these uprights at each end of the framework, which serve to attach member 10 to the timbers 12, the member 10', the" timbers 12 and the uprights 14 thus constituting a rectangular framework substantially twice the length of the wing to .be doped, and sufficiently wide to accomodate a single wing. f a

Carried .by the underside of the member 10 is a trolley or track, which as shown consists of two members 20 having inturned flanges 21 adapted to act as a track for receiving the trolley wheels 22. Each of the trolley wheels '22- is rotatably mounted on a shaft 23 which is in turn carried by a standard 24 firmly attached to the upper member 26 of a wing carrying frame 25,

As shown the wingcarrying frame 25 has attached to the upper side thereof two of the standards 24 and each of these standards carries, on the shaft 23 two trolley wheels 22.

The wing carrying frame 25 consists of a wooden frame composed of wooden parts'26 and 27 which constitute the upper and lower sides of such frame, and of wooden members 28 and 29 which constitute the ends of 27- are a plurality of standards 40 each of which carries a roller 41. The timbers 12v are so placed and the standards 40 and rollers 41 are so mounted on the lower frame member 29 that these rollers cooperate with the inner faces of the timbers 12 which thus constitute-guides or tracks to maintain the frame 25 in position as it slides'back and.

forth along the trolley or track 20. Carried by the lower member 27 of the frame 20 area plurality of supportingblocks 30 .upon" which the wing to be doped is sup'-' ported in the frame. Carried by the upper Carried by the lower member member 26 of the frame 20 is a pivoted snpporting block 31. Each of these supporting blocks has therein a groove adapted to re ceive the edge of the wing to thus holdthe wing firmly and steadily in place within the ing from one end thereof, the frame work is enclosed so as to form a chamber or booth silfliciently large to completely enclose the track and carrying frame mounted thereon.

In actual practice-this booth consists of a chamber closed on all four sides and at one end, the other end, the end intermediate the ends of the framework, being open. This booth is of sufficient length to completely receive and, enclose the wing carrying frame and the wing carriedthereby- Lo-.

cated within the booth, which is designated -by the numeral are heating coils adapted to receive steam or hot water for raising the temperature of the atmosphere within the booth. The flow of steam or hot water through the heating coils 60 is controlled by a valve 61 by means of which the temperature within the booth may be prop-- 'erly regulated.

means for controlling the valve 61 to auto-I If desired thermostatic matically maintain a predetermined temperature in the booth may be-used, but such controlling means is not a necessity.

Leading off from the tOPT Of the booth and from the bottom thereof are a plurality of ventilatingpipes 70 each of which opens .conventional kind.(not shown) adapted to.

into a ma1n"71, which is in turn operatively connected with a pump or blower of some remove from the booth the solvent material evaporated during the drying of the dope.

As shown in 1 of the drawing, that part of the framework which is not surrounded by' the booth-55 is broken away. This part of the frame work, however, is of sufficient length to accommodate' the entire wing carrylngframe 25. Whenit is desired to dope a wing, the wing carrying frame 25 is slid outwardly along the track 20 untilit is completely without the booth- The wing is then placed in the supporting blocks 30, the upper pivoted supporting block 31 being swung upon its pivot to permit of proper positioning-of the wing, after which this block is moved into contact with the wing which is in this manner held firmlyin place during the doping operations.

In doping with this type of apparatus, the

' operators stand adjacent the open end of Y the booth 55 and apply the dope to the fabric covering by means of hand or air brushes. If desired mechanical means for applying the dope, such as mechanically operated brushes, may be used in place of manual.

means, As the dope is applied to the fabric the frame 25 is moved along the track and into the booth, so that the doped portions of the wing will dry in the conditioned -at-.

mosphere within the booth.

In Figs. 3 and 4 I have shown a modified 82. This framework, like the framework of themodification shown in Figsl and 2, is rectangular in shape, the length of ti c framework being a little more than three times the length of the wing, or other piece of apparatus, to be treated therein, and sufficiently wide to accommodate the three carrying frames, arranged in parallel.

Arranged upon the floor intermediate the beams 82 are three tracks 90, each of which extends the entire length of the framework. Each of, these tracks carries upon the upper face thereof a rod, or pipe, 91 adapted to serve as the track proper, upon which is supported a wing carrying frame 100, and along which said wing carrying frame is adapted to be slid to assume any desired po-. sition throughout the length of the framework. Each of the wing carrying frames 100' consists of a rectangular wooden frame, similar to that described above in connection with Fig. 1,-having upon the lower member thereof a plurality of supporting blocks, and upon the upper member a pivoted supporting block, for holding the wing steadily within the frame. Each of the wing carrying frames has mounted upon the lower member thereof a plurality or rollers 101, each of which is rotatably mounted upon a shaft 102, carried by the members 103 which are, in turn rigidly attached to the lower member of the frame. Attached to each of the members 103 isa guard or protector 104 adapted to overlie the rollers. 101 and the track 90, to prevent any dope falling there-- upon and interferring with the ready working of the device. Also carried by the wing carrying frame 100 and rigidly attached to the upper member thereof are a plurality of standards 105, each of which carries two rollers 106. These rollersare so positioned with reference to the framework members that whenin operative position they con: tact with such members 80, which thus serve as guides and hold the wing carrying frame properly positioned upon the track 90.

In this modification of the device two drying booths are provided. One of these, 110, extends from one end of the framework and incloses a sufficient length of the entire framework, including the three tracks .within the framework, to house completely three i r I of the wing carrying frames. The other (if these booths, 115, is located intermedlate the 4 ends. of the framework and is'so positioned with referenceto the firstementioned booth that a space 140 between the adjacent ends of thetwo isleft, which is sufficiently large to accommodate; two workmen ,or operators,

1 7 one upon each side of theftracks. This booth is of substantially the same length as the first mentiohedbooth, 110,; being thus .of

such sizeas toinclose completely the three a p urality of swinging doors 116, one for 'each of the tracks 90.. These doors may be swung open to permit of sliding the wing carrying frames along the tracks iinto the booth 115, and, after such wing carrying frames are completely within the'booth, may

"be closed, thus leaving this booth open at only one end, as is the case with booth 110.

The entire length of the framework is such that a suficient length of it is uninclosed, beyond the door end of the bo'oth 115, to accommodate .upon each track, in such uninclosed portion,an entire wing carrying frame being control" ed by means of valves 121. If

desired the valves 121 may be controlled by The booths 110 and 115 have heating coils 120 therein, the flow of steam, hot water or "other heat1n medium within these coils thermostatic means to automatically maintain a "Leadin off from the booths 110 and 115 are venti atlng pipes 130 each of which leads into the ventilating main 131 which has therein a blower, or .pump, (not shown), of any conventional type for removing from the booths thesolventladen atmosphere resulting from the drying of the doped wings.

As in Figs. 1 and 2, the apparatus is shown ,as partly broken away in order to disclose the entire apparatus in one 'view.- h

. Thesa-me method of doping may of-course befcarried out in both types of apparatus disclosedfand described above. above, in the present accepted practice in airplane construction, each wingor other fabric covered part of an airplane which is treated with dope is given four coats of the dope, after which it is enameled. With the apparatus shown in Fig. 1, a wing is mount- -ed within the. .wing carrying frame and doped as the frame is gradually moved forward carrying the dopedpart of the wing "into the drying booth. After the doping is c'ompletedfthe winglis left within the drypredetermined temperature within the-boot As stated jmoaere -ing booth about 10 minutesto permit of the" complete-drying out of all the solvent. The

doping wings in the apparatus dis-' closed in'ljigs. 3 and 4 the method is fundamentally the same, but because of structural differences thisdoping apparatus lends itself to more efficient carrying on of the work. In using this type of apparatus the three wing carrying frames are moved to the 4 uninclosed portion of the framework and the wingsto be doped are mounted there- Wlllg carrying frame is then drawn out of. the booth. and the Wing given another coatin. i The doors 116 are then opened and the three frames, with the wings therein, are moved into the booth 115. The doors 116 are then closed. The operators stand in the space 140 between the two booths 110 and 115. The wings are gradually moved, one. at a time, ,from the booth 115 to the 'dopea complete wing with two operators working upon it. By the time the third wing is completely doped the first wing has been within the drying booth for ten minutes and is therefore completely dry and ready for the second coating. The wings are then moved successively from booth 110 back into booth 115 being again doped as they pass through the space 140. And this operation is repeated until each wing has received four coats and is completely doped. At the close of this doping operation the three wings will be in booth 115. It is therefore merely necessary to allow a ten-minute dwell to permit of the complete drying of the last wing, after which the doors 116 are opened, the wing carrying frames slid out upon the uninclosed portion of the tracks, the wings removed therefrom, new wings mounted inthe frames to take their places andthe sequence of doping operations resumed. It is obvious that this form of doping apparatus lends itself to very efficient work. It is equally obvious that the number of tracks within the drying booths, and therefore thenumber of wings which may be included in one sequence of doping operations, is purely a question of expediency. Andthis number may be increased or decr'easedas desired, to secure the best results;

riod as set out above is found insufficient.

slidably mounted on said I While I have described my method of doping to prevent blooming in connection with apparatus comprising heating coils for lowering the relative humidity of the drying atmosphere, I Wish viously other means for lowering the relative humidity of the drying atmosphere might be devised, such a means for instance being, as stated above, a refrigerating apparatus for condensing the moisture in the atmosphere before it is introduced into the drying booths, and my invention therefore is not-to be limitedin its scope to this precise disclosure. Y I

Whilethe method herein described,- and the forms of apparatus for carryingthis i method into efiect, constitute preferred embodiments of the invention, it is to ,be understood that the invention is not limited to this precise method and apparatus, and that changes may be made in either Without departing from the scope of the invention which. is defined in the appended claims.

What I claim is as follows:

1. In an apparatus for doping the fabric covering of airplane parts, a track; a frame track and adapted it expressly understood that it is by no means limited to this specific means of securing this desired result. Ob-

for carrying therein the part to be doped; and a plurality of booths surrounding said track, each booth adapted to receive and completely house the frame.-

2. In an apparatus for doping the fabric covering of airplane parts, a track; a frame slidably mounted on said track and adapter for-carrying therein the part to be doped;

a plurality of booths surrounding said track of all of the tracks; a portion of each track at one end being uninclosed by the booths; and means for opening or closing the end of the booth'adj acent the uninclosed portion of the tracks.

In testimony whereof I afiix my signature.

FRANK O. (ELEMENTS. Witnesses:

THOMLAS MIDGLEY, J r., H. C. MOUGEY. 

